avoid injecting into the grid

OffGridInTheCity

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Thanks guys!

@Daromer - yea, the BMS will stay on because I'm going to parallel itinto the house battery bank when the trailer is offline -so the battery will be charged / in regular use.


And... back to the original post / thread that I hijacked.. I am pleased with simplicity/functionality ofMppSolar PIP and concur the UPS works great - no need for a separate UPS system like I have with Midnite Solar + AIMS combo in my main system. And if I read it right - you can gang several of these PIPs and get up to 15kw of power - e.g. full house-hold level power at 240v US.
 

not2bme

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freshter said:
I had someone come by to make an offer for an installation. They're offering Q Cells Q-Peak BLK G8+ 340 W panels (30 panels). All panels would have optimizers connected.

I'd have 14 panels oriented east 336 degrees and 16 panels oriented west 157 degrees. Roof inclination is 38 degrees. I'm at longtitude 4.8547 latitude 50.837.

They're also proposing a SolarEdge 3 phase inverter either SE 5K or SE 7K.

In this setup I would inject back to the grid for at least 15 years as my meter would turn backwards. That gives me 15 years to come up with a solution for a powerwall :) I'd have 25 years warranty on the full setup.

How should I size the inverter? I'd have a yearly fee of 87 euros per 1kw maximum inverter output so I better don't size it too large.

In my opinion, under 10 years is acceptable, but 15 years is a long time. That 25 year warranty on the panels is pretty much uncliamable unless there was a major manufacturer's defect, and I mean major. I doubt anyone's been able to claim anything. The inverters are probably 5 years at most. The optimizers are probably similar. Also another major factor is the roof. In my area it's mostly asphalt shingles and they only have a lifespan of 20 years. So you would never put solar on a 10 year old roof. The added cost to remove the panels and replace the roof would just add to it. Also adding batteries will mean more equipment, as those are not free, so I won't be surprised if adding the additional ac coupled inverter and batteries might not be as beneficial as you'd like it to be, just because your grid-tie up front cost was high. Now if you can plan it so that you know that the solaredge inverter is indeed a hybrid, so it is capable of accepting a custom 48V battery and not tied to a specific brand like lg. That way it's one more equipment out of the way.
 

Cheap 4-life

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OffGridInTheCity said:
Thanks guys!

@Daromer - yea, the BMS will stay on because I'm going to parallel itinto the house battery bank when the trailer is offline -so the battery will be charged / in regular use.


And... back to the original post / thread that I hijacked.. I am pleased with simplicity/functionality ofMppSolar PIP and concur the UPS works great - no need for a separate UPS system like I have with Midnite Solar + AIMS combo in my main system. And if I read it right - you can gang several of these PIPs and get up to 15kw of power - e.g. full house-hold level power at 240v US.

I think I read that 2 of the 120v can supply splitphase. Or is it better to use a separate transformer to make splitphase wired into the ac out off the 240v single phase Mpp PiP. I think I seen offgrid steve get splitphase from one of these 240v inverters that way. Or is it better to use a separate 120v inverter for 120v loads
 

daromer

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cheap-4-life
You can use transformer to do the split phase yes but always when doing such you loose some energy and a split phase transformer that size cost more than getting a unit that can do it directly or 2 single phase that can be hooked up doing it.


no2bme
Warranty on panels generally is 5-10 years in terms of normal use but power generation is up to 25 years. But to claim those 25 years you can not have hurt the panel in any way during the normal warranty claims.
Ie it shall produce a minimum set of wattage during 25 years BUT.. They only give you functional guaranty for 5-10 years to actually work or withstand weather.. Atleast some i read have been like that :D
 

freshter

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In the end I'll be building my own solar setup.

I'm looking to buy panels online and I'm eyeing these panels right now:


I have zero experience with panels and brands. Is there any reason I should not get any of these panels?

For the inverter I've been looking at victron models, but it seems only these victron inverters are allowed to be connected to the grid in my country:
  • Multiplus-II 48/3000/35-32
  • Multiplus-II 48/3000/35-32 GX
  • Multiplus-II 48/5000/70-50
Are these so called hybrid inverters?

I don't think any of these can provide enough power though on the AC side for a setup of 16 panels east, 16 panels west on a normal saddle roof.
 

daromer

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I dont know the Victron so wont comment on them but i can comment on the panels

First of all you have 2 different size panels in the list. You have 60 cell ans 72 cells. If you are cramped on space the Longi panels have the highest output per m2.
I would personally buy the ones with best cost/wattage. I would also look at the warranty on the panels. Nowadays almost all panels have 25 years warranty on 80% minimum power output. Look at those curves and compare. Some degrades faster than others...
With that said panels today is more of cost per wattage i would say.
 

grundholm

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You will need a charge controller and a battery with the Victron MultiPlus II and the GX model has the VE.Can build in (USB, Ethernet and VE.Direct for communication with other Victron devices) - I have been looking at this inverter myself and I think it seems very nice, I just can't find any information on how to use it with a selv-build batterypack.

A nice thing (IMO) is that you can use it as a UPS - it has two output connections one for the more 'heavy' loads and one that acts like a UPS.

I think the reason why it's legal (and probably also without any registration) is because it does not inject power to the grid, it only use the grid to add the power that your batteries(solar) can't provide.

The MultiPlus II is a one fase inverter, if you want to connect all 3 fases, then you need 3 inverters or rearrange your fusebox.

https://www.victronenergy.de/upload/documents/Datasheet-MultiPlus-II-GX-inverter-charger-DE.pdf

another option for solar panels could be:
Trina Solar Honey Black TSM-330-DD06M.05
They make a DE and DD model - the DD is all black!
 

Roland W

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Grid-tied systems are the easiest and mostly cheapest way to get into the PV game. Every Inverter company (1st tier, 2nd tier) has numerous offers on 1-phase or 3-phase devices in a range from 1kW to up to 100kW and even more. There are no 1 or 2 tier inverters which do not feature basic safety functions like "anti islanding, etc", so no killing of linemen there.
But all those systems do have in common, that you need to have a talk with your utility.
Most countries will have either net-metering or feed in tariff schemes coming with your connection. For those contracts, you do not need to limit or nullify your export. Get something payed for it, but if that is not as much as you would like to get, think about storing into batteries (aka peak shaving)

But some countries still won't have that options for private customers. Those places typically offer legal grid-tied PV by using Export Limiters, Zero export meters,... or whatever they call it there.
Its just an extra connected CT to the inverter. So the inverter must be featuring that option.

Important to say is, that if you later want to as well store you excessive power into a battery, you need to have a PV system, which does NOT limit your free flow of energy. Because otherwise there is no way for the battery controller to tell if there is excess there or not. For that (Limited AND battery) only a Hybrid inverter could do the job, as it knows how much it limited output before charging.
Hybrid systems are typically more expensive, same as are off-grid systems.

The Tesla (and other Buywalls) are typically the easy way. Metering at the gate and catch up the excess energy via their built-in charger/inverter. So you need that permission!
Can something like that be done DIY for 1/3 of the price? Yes it can. I have the prove of concept running on my property. Please ring me for infos if you don't know about it yet...
 

copec

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FWIW My municipality will only give out permits for grid-tie systems, and it has to use all UL listed components, be signed off by an engineer, and be installed by an electrician. I wanted to use cheap Chinese/Taiwanese components, used solar panels from a solar plant, a home made battery, and my own labor, for which none were listed or legal. So I ignored my municipality. Even people who have some part of their whole system legal on this forum, are most likely illegal by attaching a home built battery to their house.
 

Roland W

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copec said:
Even people who have some part of their whole system legal on this forum, are most likely illegal by attaching a home built battery to their house.

Of course, but who cares. If you have permit to export to the grid, you as well have a permit to export less. If you add a DIY battery to your system and let say capture half of the power you else would have exported, will the utility get suspicious and ask who the mayor or your city, to go to your house and flip the basement to find some 18650s laying around somewhere? You could as well just have bought a new electric appliance or EV and are using more energy now. Officials want you to buy the newest expensive equipment from companies, they don't want you to go to scrapyards and find recicleable stuff. In some countries even that is illegal! No taxes to collect there. But if people would just obey authorities, this forum wouldn't exist, right?
 

Cheap 4-life

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There is grid tie inverters out there (more than one) that allow the user to avoid talking to the utility at all. Zero export, limiting etc. This imo is a better option financially. User can then save all the excess power they want to that their solar produces by increasing the size of their battery bank. Batteries are becoming cheaper. Exporting power to the utility to buy back later can lead to minimal savings. In my area and many areas of the USA, the electric companies say a home owner can not touch any part of the renewable install. For me that meant $26000 to have the size setup that I installed myself for $7000. I wouldnt spend 26k for electricity in a lifetime. So I ignored them because in the end my money is more important than their rules.
 

OffGridInTheCity

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copec said:
FWIW My municipality will only give out permits for grid-tie systems, and it has to use all UL listed components, be signed off by an engineer, and be installed by an electrician. I wanted to use cheap Chinese/Taiwanese components, used solar panels from a solar plant, a home made battery, and my own labor, for which none were listed or legal. So I ignored my municipality. Even people who have some part of their whole system legal on this forum, are most likely illegal by attaching a home built battery to their house.
In my city (Southern Oregon USA)it was no problem getting apermit - there were 2 inspectors involved. Structural (panels on the roof) and Electrical. My system is offgrid. They didn'tdistinguish between grid vs off-grid as that's covered in the 'electrical' sign-off. I was required to hire an electrician 'of record' for the permit - but as the homeowner I can dothe work myself. I was required to have rapid shutdown, all UL or ETL listed equipment, meet conduit codes (48vdc must be in conduit) etc. All no problem... except as you say 'the battery' was a mystery to my electrician.

The city electrical inspector didn't care one bit about the battery or details of it - he just wanted to see that *the output of the system*and once he discovered it was nottied to the grid and he just signed off on the wiring/conduit that components had UL/ETL stickers etc, He didn't ask any questions on the battery even though he was standing right next to it :)

I'm not saying your experience would be like mine / my jurisdiction - just sharing how it worked for me.
 

copec

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OffGridInTheCity said:
I'm not saying your experience would be like mine / my jurisdiction - just sharing how it worked for me.

I wish my city was like yours. I doubt they will notice or enforce the codes though, my whole city is filled with obvious violations even on my street and none of them have ever had anybody contact them about it.
 

daromer

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I had the electric company to come and visit me to crosscheck. I was feeding into grid during the night and that should not be possible with a solar install. They called me same minute when they were outside said "we are going to check this because its wrong". My answer was "Sure you do that. Please also read the papers and you will see that i have a approved solar system that is grid-tied with battery bank capabilities"

5 hours later they left and havent heard from them since then. I guess they did check their stuff and then gave up. Since it says in the papers what type of inverter i have and that electrician have checked those points that currently in sweden is needed to get it approved :p

So legal aspects differ in different places.
 

Overmind

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Looks like a very long talk in here.

Why not just mount a 2-position switch ?

This way you can use the grid when you want and your own system when needed.

Adding a relay to that can even make thinks work automatically in the case the grid is offline.

Otherwise, legal aspects may be more painful than everything else combined.
 

daromer

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Yes ATS with mechanical and electrical protection or an 1-0-2 switch works fine and is legal in most places. Best and easist way doing it :)
 

OffGridInTheCity

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daromer said:
Yes ATS with mechanical and electrical protection or an 1-0-2 switch works fine and is legal in most places. Best and easist way doing it :)
Yes, I use several ATS(s) for my off-grid system. I turn my inverter on/off automatically based on battery voltage. When the inverter turns on / supplies power to the ATS, the ATS will switch to that source of power. When the inverter is turned off the ATS switches back to grid power. All automatic and I'm safely *not* connected to the grid.

Here's a visual on Dec 5th of grid consumption drop after the inverter came on and produced 21kwh that day...
image_rfknaq.jpg

There are somecaveats...
-You may need some key UPSs for equipment affected by the switchovers.. e.g.computers etc.
- You cannot send 'excess' power to the grid - so my system / circuits aredesigned to power 80% - e.g. cannot exceed 100%.
- Potential'surge' during switchovers as the sine waves (when using dumb ATSs) are not matched between the 2 sources of power as they switchand I read that thiscan induce a power surge in certain motors- but I've not hadtrouble with any motors (refrigerators or furnace or AC compressor). The manufacturer of the UL listed ATS says they've never had a report of a problem.

PIP has advanced ATS'ing capabilities that apparently mitigate both UPS and Sine-wave issues I understand.

For me - its been 2.5 years @ 2 switch-overs per day... I'm now approaching 2,000 successful ATS switchovers :)
 

daromer

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also note that some ats switches arent rated to many switches. some below 1000.... Just and FIY.
 

OffGridInTheCity

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daromer said:
also note that some ats switches arent rated to many switches. some below 1000.... Just and FIY.
Agreed. I use UL listed "Progressive Dynamics PD52DCSV Surge Protected" for 240v@50a switchingthat claim 100,000+ switches and RV favorite "Go-Power 30a" which is ETL for simpler 120v@30a switching. The physicalrelays seem substantial. No problems so far butwe'll see how long they last :)
 
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